This invention relates generally to an improved roof support pin, and more particularly to an improved construction of an elongate rod and of a roof support plate for inserting the rod into the roof strata, and for precluding removal of the rod after insertion upon application of a longitudinal axial load force applied by the roof through the rod.
In the heretofore conventional roof support pins, one type of such pin utilized an expansion shell that was positively expanded against the wall of a preformed hole, after the pin had been fully inserted, to grip the wall and anchor the pin. This type of roof pin with an expansion shell provided an initial, adequate holding force but such force deteriorated with time as the wall of the roof strata engaging the expansion shell changed its characteristics. Another type of roof support pin included an elongate tube having a longitudinal split which allowed the tube to be reduced in size as the tube was forced into a preformed hole of smaller cross sectional dimension. This split tube type of roof support pin provided usually an inadequate initial holding force with the roof strata, but was more effective as time passed and relative lateral shifting of the roof strata occurred, causing deformation of the tube.